I don't think I could choose between Super Mario Galaxy 1 and 2 if someone held a gun to my head. 1 has the atmosphere, but 2 has the better difficulty progression and better leveldesign. And you know what? I don't need to choose. I love them both, but in different ways. God, that sounds as if they were my children...

But really, Galaxy 1 and 2 are both phenomenal games. When does that ever happen? A game and its sequel being equally amazing.